How to align content to the center of an element?

Question

JavaScript

Learning Semantic-UI-React
Need to center everything

<Container text >
      <Menu secondary >
        <Menu.Item as='a' header>
          <Image size='mini' src='../logo.svg' style={{ marginRight: '1.5em' }} />
          Test
        </Menu.Item>
        <Menu.Item name='Test1' active={props.activeItem === 'home'} onClick={props.handleItemClick} />
        <Menu.Item
          name='Test2'
          active={props.activeItem === 'messages'}
          onClick={props.handleItemClick}
        />
      </Menu>
    </Container>